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Comment by edelbitter | Hacker News Reader

Some scientific endeavors can be paused and maybe later relaunched, if funding has not dried up and temporarily-worthless machinery has not been left to rot.

But stuff like mitigating the constant threat of big enough objects showing up on a collision course with earth should not be paused until those eye-catchers fall out of the sky. If there is something coming at us that can wipe out more than the stock price of one particularly space-enthusiastic company, we should like to know within a time period appropriate for our current planetary defense capabilities. Which will surely improve, over time - so maybe we can pollute the sky, later.

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>the constant threat of big enough objects showing up on a collision course with earth

I don't really think this is a serious risk. This is a once-in-a-million-years kind of event.

Also, asteroid detection is not seriously affected by satellites. We can easily tell the difference between a moving satellite and a moving asteroid because of their speed.

We might have even seen the Chelyabinsk one coming, with current tech.. if only it had been coming at us from a slightly less bright direction. That one was probably in the once-in-a-hundred-years category.

That's exactly the thing space asteroid hunting telescopes solve - you can put them insuch a heliocentric orbit that they can watch for those asteroids coming from the direction of the sun.

> I don't really think this is a serious risk. This is a once-in-a-million-years kind of event.

Perhaps the last event was one million years ago and we are now (proverbially) 'due'.

> The gambler's fallacy, also known as the Monte Carlo fallacy or the fallacy of the maturity of chances, is the belief that an independent and equally probable outcome which happened less frequently than expected is more likely to happen in the future (or vice versa).

* https://en.wikipedia.org/wiki/Gambler%27s_fallacy

It's like people who say "it sure is strange that we had a 'once-in-a-century flood' two years in a row": that's not how odds/probabilities work.

* https://www.usgs.gov/faqs/we-had-a-100-year-flood-two-years-...

> It's like people who say "it sure is strange that we had a 'once-in-a-century flood' two years in a row": that's not how odds/probabilities work.

That usually refers to climate change and the fact that the odds have changed against our favor.

> Perhaps the last event was one million years ago and we are now (proverbially) 'due'.

Ironically this is a great example of the gambler's fallacy.

Hence the use of "proverbially" and "due" being in quotation marks.

Asteroid detection is certainly affected by satellites. The ever increasing number of satellites makes observations that normally detect asteroids very difficult. It is very easy to miss asteroids we would have seen otherwise if not for satellites giving off glare, reflections, and light. We don't just look for asteroids coming directly towards earth, we keep track of all sorts of large objects and their orbits in our solar system. The tracking authority is usually the IAUC Minor Planet Center.

This is why we have things like NEO Surveyor planned: space-based space rock detection.

That "particularly space-enthusiastic company" is a big part of why we're in a decent place for orbital defense right now. SpaceX has a lot of launchers, and a steady enough launch cadence that they can put a payload up there really fast, if there is a reason to hurry. Before, there was a very real risk of having to wait months just to get a launcher lined up - now, that's not nearly as much of a problem.

The year is 2026. Surely the orbits of all the satellites are known well enough, and optics are modelled well enough for telescopes to know which few pixels to ignore at any given moment?

Light scatters in the atmosphere, it's the same reason you can shine a laser beam and see it even though the light should be collimated. With enough sources of light, you end up with more background light pollution.

There's at least two issues with this line of thinking:

1. many astronomical observations are long integrations (many minutes of open shutter) and you often cannot read out the pixels during the exposure. So you can't selectively ignore pixels on a "by moment" basis. And with enough satellites, enough pixels could be affected to render an entire image effectively unusable

2. It seems you're thinking only about optical astronomy. There's also a ton of radio/millimeter wave astronomy that's done from the ground. Satellites have radio-wave downlinks that can be powerful enough to destroy the electronics used in radio astronomy receivers. The US's National Radio Astronomy Observatory has been working on data sharing with Starlink to mitigate this, but it's basically up to companies to agree to work together. Other satellites / companies don't engage in this coordination and so some radio telescopes need to go to a "safe"/stow position to protect the electronics. This costs valuable observing time.

How about putting our astronomy experiments into space as well? There'd be no light / em pollution there, as well as no atmospheric interference etc. and, 24/7 free power courtesy of our sun. Id expect orbital observatories to be superior to ground based ones, thinking of Webb, Hubble.

I suppose the only downside is cost. So, the actual problem, is how to tax the shared resource that is our LEO. Aside from that, wed also want to incentivize not leaving space debris in orbit. Require insurance, and perhaps rent for orbital trajectories?

But, without working international order, theres no way thats gonna happen...

Radio telescopes are hilariously massive. I'm not sure it'd be easy to reproduce their capabilities in space?

Why not? They are massive only because you are limited by earth surface. In space there are no limits, see Radioastron for example, and that was decades ago.

Right now for the price of that one project one could have a humongous radio telescope in orbit without any interference. If only people could really look forward.

> In space there are no limits, see Radioastron for example, and that was decades ago.

Radioastron required cross-correlating the signal with ground-based radio teleacopes in order to do science. The collecting area, dish distributons, etc. would need to be fully replicated in space if one wanted to avoid using ground-based facilities entirely.

Nope. Ot was one of a kind thing only because you could not launch two at the time. With that a-given, ofc the ground-based "other end of the leg" was essential for it to work.

Now we can launch two. Or two dozen. This completely obviates any need for ground listeners as for resulting angular resolution.

Since ground-based radioastronomy has other uses, will stay there anyway and since crosscheck is always better, future long-base radiointerferometry will use legacy ground-based observatories.

We're saying the same thing -- one radioastron satellite isn't enough, you'd need a constellation of them.

> How about putting our astronomy experiments into space as well? There'd be no light / em pollution there, as well as no atmospheric interference etc.

One would need to put the telescopes into fairly high orbits in order to avoid the interference. I think that even images made with the Hubble space telescope have sometimes seen the impact of satellite constellations.

When science is already experiencing a funding stranglehold, how do you expect researchers to have access to do experiments in space?

Is that sort of research unavoidably impaired by a more crowded night sky? Or do we just have to spend more to collect the same quality of data from more or better terrestrial observatories?

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